Vending machines include an interior which houses food products and is cooled by a refrigeration system. The food products are disposed in the interior to be commonly cooled. A heat exchanger is disposed in the interior and one or more fans blow air across the heat exchanger to cool the air in the interior. The cooled air then cools the food products concurrently. In a basic design of a beverage machine, the machine is divided into two chambers—the lower chamber to house the refrigeration system, generally a vapor compression system, and the upper chamber to house the stack of beverage cans or bottles. The beverage cans and bottles are loaded vertically or horizontally and then dispensed by gravity into the dispensing chute. The entire upper chamber is cooled in these machines.
Vending machines generally are made in three sizes—small, medium and large. Typically the beverage can capacity of the small machines is 100 to 300 cans, of the medium 300 to 800 cans and of the large 800 to 1,500 cans. The steady state power consumption to maintain the machines at the beverage dispensing temperature in the range 36° F. to 38° F. is 325 W for small, 800 W for the medium and 1,200 W for the large machines. The steady state energy consumption is a component of the cost associated with operating the vending machine.